<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<body>
<script>
// TODO(crbug.com/1231615): We were not able to test this with reference tests.
test(function(t) {
    var canvas, ctx;
    canvas = document.createElement("canvas");
    canvas.width = 200;
    canvas.height = 200;
    document.body.appendChild(canvas);

    ctx = canvas.getContext("2d");
    ctx.fillStyle = 'rgba(0,0,255,1)';
    ctx.fillRect(60,60,75,50);
    ctx.globalAlpha = 0.3;

    ctx.beginLayer();

    ctx.fillStyle = 'rgba(225,0,0,1)';
    ctx.fillRect(50,50,75,50);
    ctx.fillStyle = 'rgba(0,255,0,1)';
    ctx.fillRect(70,70,75,50);

    ctx.endLayer();

    var overlap = ctx.getImageData(71,71,1,1);

    assert_approx_equals(overlap.data[0], 0, 2);
    assert_approx_equals(overlap.data[1], 76, 2);
    assert_approx_equals(overlap.data[2], 178, 2);
    assert_approx_equals(overlap.data[3], 255, 2);

}, "Test that ensure layers work for global alpha.");
</script>
</body>